Inorganic environment-friendly additive for improving shakeout performance of clay molding sand and application of inorganic environment-friendly additive in clay molding sand

Abstract

The invention relates to an inorganic environment-friendly additive for improving the shakeout performance of clay molding sand. The additive is a silicate aqueous solution containing one or more of potassium, sodium and lithium. The invention also provides application of the additive in clay molding sand. According to the inorganic environment-friendly additive disclosed by the invention, the problems of high residual strength and poor shakeout performance of high-density molding clay molding sand can be solved, the production efficiency can be improved, waste sand discharge can be reduced, and resource consumption can be relieved.

Description

Technical Field

[0001] The invention belongs to the technical field of clay sand casting, and particularly relates to an inorganic environmentally friendly additive for improving the falling sand performance of clay sand and an application of the inorganic environmentally friendly additive in the clay sand. Background Art

[0002] The Chinese civilization has a long history, and casting is an indispensable part of it. Today, the foundry industry is the basic industry of equipment manufacturing, and the technical level of the foundry industry can measure a country's industrial level and economic development level to a certain extent.

[0003] With the advancement of casting technology, high-density molding of clay sand has developed rapidly as a new process in mass production. The production efficiency of high-density molding of clay sand is high, and the castings produced have the advantages of precise size, smooth surface, dense structure, and high mechanical properties. However, the sand mold of high-density molding of clay sand has high strength and high compactness, which leads to high residual strength and poor sand falling performance after the casting of the sand, especially when casting castings with inner cavities, the sand in the inner cavity is more difficult to fall out and clean. The sand falling performance of clay sand is not only related to production efficiency, but also affects the recycling of old sand in high-density molding.

[0004] At present, the additives for improving the sand falling performance of the molding sand are mainly for water glass sand molds, and there are no additives for improving the sand falling performance of clay molding sand. Therefore, there is a need for an additive that does not affect the various performance indicators of clay molding sand, ensures successful pouring, and can help with sand falling and cleaning processes after pouring is completed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a green and environmentally friendly inorganic additive, which is non-combustible and emission-free, reduces the residual strength of clay sand, and improves the sand falling performance of clay sand in high-density molding.

[0006] The invention provides an inorganic environmentally friendly additive for improving the falling sand performance of clay molding sand. The additive is a silicate aqueous solution containing one or more of potassium, sodium and lithium.

[0007] Preferably, the modulus of the silicate aqueous solution is 2 to 10 and the density is 1.0 to 2.6 g / cm 3 .

[0008] The present invention also provides an application of the additive in clay molding sand. Calculated by weight, with the mass of the original sand as 100 parts, the weight ratio of the components of the molding sand is original sand: water: clay: additive = 100: 2-10: 2-20: 0.2-10.

[0009] The raw sand is quartz silica sand or non-quartz raw sand.

[0010] Preferably, the original sand particle size is 20-200 mesh.

[0011] More preferably, the non-quartz raw sand is gemstone sand.

[0012] The clay is calcium-based bentonite, sodium-based bentonite, lithium-based bentonite, common clay or refractory clay.

[0013] Preferably, the clay is sodium bentonite.

[0014] Furthermore, the mixing method of the clay molding sand is to first add bentonite (or water) to the original sand and mix evenly, then add water (or bentonite) and mix evenly, and finally add additives and mix evenly before producing the sand.

[0015] Preferably, the weight ratio of the components of the clay molding sand is raw sand: water: clay: additive = 100: 2.8: 8: 0.5, the raw sand is 50 / 100 mesh quartz sand, the clay is sodium bentonite, and the additive has a modulus of 2.3 and a density of 1.51 g / cm 3 of sodium silicate aqueous solution.

[0016] Preferably, the weight ratio of the components of the clay molding sand is raw sand: water: clay: additive = 100: 3.2: 8: 0.3, the raw sand is 70 / 140 mesh quartz sand, the clay is sodium bentonite, and the additive has a modulus of 2.4 and a density of 1.52 g / cm 3 A mixed aqueous solution of potassium and sodium silicates.

[0017] Preferably, the weight ratio of the components of the clay molding sand is raw sand: water: clay: additive = 100: 2.8: 8: 0.5, the raw sand is 50 / 100 mesh quartz sand, the clay is sodium bentonite, and the additive has a modulus of 4.8 and a density of 1.18 g / cm 3 Aqueous solution of lithium silicate.

[0018] Preferably, the weight ratio of the components of the clay molding sand is raw sand: water: clay: additive = 100: 2.5: 8: 0.5, the raw sand is 70 / 140 mesh quartz sand, the clay is sodium bentonite, and the additive has a modulus of 3.9 and a density of 1.24 g / cm 3 Aqueous solution of potassium silicate.

[0019] Preferably, the weight ratio of the components of the clay sand is Yunxi environmentally friendly sand: additive = 100:0.25, and the additive has a modulus of 2.3 and a density of 1.51 g / cm 3 of sodium silicate aqueous solution.

[0020] Preferably, the weight ratio of the components of the clay molding sand is raw sand: water: clay: additive = 100: 2: 8: 0.5, the raw sand is 50 / 100 mesh pearl sand, the clay is sodium bentonite, and the additive has a modulus of 2.3 and a density of 1.51 g / cm 3 of sodium silicate aqueous solution.

[0021] Beneficial Effects

[0022] The additive of the invention is non-toxic and tasteless, and does not generate gas and dust during the casting process. After adding the additive, the molding sand still has sufficient strength and toughness at room temperature, can meet the requirements of high-density molding and pouring, and the residual strength of the molding sand after pouring is significantly reduced, and it is very easy to clean out, which not only saves production costs, but also reduces energy consumption; at the same time, the molding sand can be recycled, and the reuse rate is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The appearance of the casting poured in Example 5 of the present invention and the inner cavity of the casting after the sand is knocked out.

[0024] Figure 2 The appearance of the casting poured in Example 6 of the present invention and the inner cavity of the casting after the sand is knocked out. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0026] The mixed molding sand in the embodiment and the comparative example was tested for wet compressive strength at room temperature and residual strength at various temperatures. The test method is as follows:

[0027] Green compression strength test: Take 140-170g of the mixed molding sand and use the SAC hammer sample maker to make a Φ50mm×50mm cylindrical sample. The test can be carried out if the height deviation of the mold sand sample is within 1mm. Use the SWX digital universal strength tester to test the green compression strength of the molding sand.

[0028] Residual strength test at different temperatures: Weigh a certain amount of mixed molding sand, use a SAC hammer sample maker to make a Φ50mm×50mm standard cylindrical specimen, push it out of the specimen tube, put it into a box-type resistance furnace that has been heated to the specified temperature, heat it for 20 minutes, take it out and air-cool it to room temperature, and then put it on a SWX digital universal strength tester to measure its compressive strength.

[0029] Example 1

[0030] The additive for improving the falling sand performance of this embodiment has a modulus of 2.3 and a density of 1.51 g / cm 3 The weight ratio of the components of the molding sand is raw sand: water: clay: additive = 100: 2.8: 8: 0.5, the raw sand is 50 / 100 mesh quartz silica sand, and the clay is sodium bentonite.

[0031] The molding sand is mixed by first adding water to the raw sand and mixing it evenly, then adding bentonite and mixing it evenly, and finally adding additives and mixing it evenly before sanding out. The mixed molding sand is recorded as sample A.

[0032] Comparative Example 1

[0033] Without adding additives, other raw material formulas and processes are the same as those of Sample A in Example 1, and the mixed molding sand is recorded as Sample A*.

[0034] Example 2

[0035] The additive for improving the falling sand performance of this embodiment has a modulus of 2.4 and a density of 1.52 g / cm 3 The weight ratio of the molding sand components is raw sand: water: clay: additive = 100: 3.2: 8: 0.3, the raw sand is 70 / 140 mesh quartz silica sand, and the clay is sodium bentonite.

[0036] The molding sand is mixed by first adding water to the raw sand and mixing it evenly, then adding bentonite and mixing it evenly, and finally adding additives and mixing it evenly before sanding out. The mixed molding sand is recorded as sample B.

[0037] Comparative Example 2

[0038] Without adding additives, other raw material formulas and processes are the same as those of Sample B in Example 2, and the mixed molding sand is recorded as Sample B*.

[0039] Example 3

[0040] The additive for improving the falling sand performance of this embodiment has a modulus of 4.8 and a density of 1.18 g / cm 3 The weight ratio of each component of the molding sand is raw sand: water: clay: additive = 100: 2.8: 8: 0.5, the raw sand is 50 / 100 mesh quartz silica sand, and the clay is sodium bentonite.

[0041] The molding sand is mixed by first adding water to the raw sand and mixing it evenly, then adding bentonite and mixing it evenly, and finally adding additives and mixing it evenly before sanding out. The mixed molding sand is recorded as sample C.

[0042] Comparative Example 3

[0043] Without adding additives, other raw material formulas and processes are the same as those of Sample C in Example 3, and the mixed molding sand is recorded as Sample C*.

[0044] Example 4

[0045] The additive for improving the falling sand performance of this embodiment has a modulus of 3.9 and a density of 1.24 g / cm 3 The weight ratio of the components of the molding sand is raw sand: water: clay: additive = 100: 2.5: 8: 0.5, the raw sand is 70 / 140 mesh quartz silica sand, and the clay is sodium bentonite.

[0046] The molding sand is mixed by first adding water to the raw sand and mixing it evenly, then adding bentonite and mixing it evenly, and finally adding additives and mixing it evenly before sanding out. The mixed molding sand is recorded as sample D.

[0047] Comparative Example 4

[0048] No additives were added, and the other raw material formulas and processes were the same as those of Sample D in Example 4. The mixed molding sand was recorded as Sample D*.

[0049] Comparative Example 5

[0050] The additive of this comparative example has a modulus of 2.3 and a density of 2.76 g / cm 3 commercially available sodium silicate aqueous solution; except for the additives, the components of the molding sand and the weight ratio are the same as those in Example 1, and the weight ratio of the components of the molding sand is raw sand: water: clay: additive = 100:2.8:8:0.5, the raw sand is 50 / 100 mesh quartz silica sand, and the clay is sodium bentonite.

[0051] The molding sand is mixed by first adding water to the raw sand and mixing it evenly, then adding bentonite and mixing it evenly, and finally adding additives and mixing it evenly before sanding out. The mixed molding sand is recorded as sample A1.

[0052] Example 5

[0053] The additive for improving the falling sand performance of this embodiment has a modulus of 2.3 and a density of 1.51 g / cm 3 The commercially available sodium silicate aqueous solution is added to the mixed Yunxi environmentally friendly sand and mixed evenly. The weight ratio of each component of the molding sand is Yunxi environmentally friendly sand: additive = 100:0.25. The mixed molding sand is cast at a pouring temperature of 1400°C and the casting material is QT500-7. After boxing, the casting is as follows Figure 1 As shown, the sand removal and cleaning process of the casting is simple, and the surface quality of the inner and outer walls is good.

[0054] Example 6

[0055] The additive for improving the falling sand performance of this embodiment has a modulus of 2.3 and a density of 1.51 g / cm 3 The commercially available sodium silicate aqueous solution. In terms of weight, the weight ratio of each component of the molding sand is raw sand: water: clay: additive = 100: 2: 8: 0.5, the raw sand is 50 / 100 mesh pearl sand, and the clay is sodium-based bentonite. The mixed molding sand is cast at a pouring temperature of 1400°C, and the casting material is QT500-7. After boxing, the casting is as follows Figure 2 As shown, the sand removal and cleaning process of the casting is simple, and the surface quality of the inner and outer walls is good.

[0056] The test results of the wet compressive strength at room temperature and the residual strength at various temperatures of the above-mentioned examples and comparative examples are shown in Table 1.

[0057] Table 1

[0058]

[0059]

[0060] “*” means no additives are added, and other raw material formulas and processes are the same as those of the corresponding example samples;

[0061] Except for the additives, the other ingredients and weight ratios of the ingredients in sample A1 are the same as those in Example 1.

[0062] According to the results in Table 1, it can be seen that the room temperature wet compressive strength of the clay sand mixed before and after the addition of the additives does not change much, but the residual strength of the sand is significantly reduced after the addition of the additives.

Claims

1. An inorganic environmentally friendly additive for improving the falling sand performance of clay molding sand, characterized in that: The additive is a silicate aqueous solution containing one or more of potassium, sodium and lithium.

2. The inorganic environmentally friendly additive according to claim 1, characterized in that: The modulus of the silicate aqueous solution is 2 to 10, and the density is 1.0 to 2.6 g / cm 3 .

3. An application of the inorganic environmentally friendly additive as claimed in claim 1 in clay molding sand, characterized in that: Calculated by weight, with the mass of raw sand as 100 parts, the weight ratio of the various components of the molding sand is raw sand: water: clay: additive = 100: 2-10: 2-20: 0.2-10. The molding sand is mixed in a sand mixer and used for molding and pouring.

4. The use of the inorganic environmentally friendly additive in clay molding sand according to claim 3, characterized in that: The raw sand is quartz silica sand or non-quartz raw sand.

5. The use of the inorganic environmentally friendly additive in clay molding sand according to claim 3, characterized in that: The original sand particle size is 20 to 200 meshes.

6. The use of the inorganic environmentally friendly additive in clay molding sand according to claim 3, characterized in that: The clay is calcium-based bentonite, sodium-based bentonite, lithium-based bentonite, common clay or refractory clay.

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